rxrpc: Support network namespacing

Support network namespacing in AF_RXRPC with the following changes:

 (1) All the local endpoint, peer and call lists, locks, counters, etc. are
     moved into the per-namespace record.

 (2) All the connection tracking is moved into the per-namespace record
     with the exception of the client connection ID tree, which is kept
     global so that connection IDs are kept unique per-machine.

 (3) Each namespace gets its own epoch.  This allows each network namespace
     to pretend to be a separate client machine.

 (4) The /proc/net/rxrpc_xxx files are now called /proc/net/rxrpc/xxx and
     the contents reflect the namespace.

fs/afs/ should be okay with this patch as it explicitly requires the current
net namespace to be init_net to permit a mount to proceed at the moment.  It
will, however, need updating so that cells, IP addresses and DNS records are
per-namespace also.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/rxrpc/Makefile

@@ -19,6 +19,7 @@ rxrpc-y := \
 	local_event.o \
 	local_object.o \
 	misc.o \
+	net_ns.o \
 	output.o \
 	peer_event.o \
 	peer_object.o \

net/rxrpc/af_rxrpc.c

@@ -38,9 +38,6 @@ MODULE_PARM_DESC(debug, "RxRPC debugging mask");
 static struct proto rxrpc_proto;
 static const struct proto_ops rxrpc_rpc_ops;
 
-/* local epoch for detecting local-end reset */
-u32 rxrpc_epoch;
-
 /* current debugging ID */
 atomic_t rxrpc_debug_id;
 
@@ -155,7 +152,7 @@ static int rxrpc_bind(struct socket *sock, struct sockaddr *saddr, int len)
 
 	memcpy(&rx->srx, srx, sizeof(rx->srx));
 
-	local = rxrpc_lookup_local(&rx->srx);
+	local = rxrpc_lookup_local(sock_net(sock->sk), &rx->srx);
 	if (IS_ERR(local)) {
 		ret = PTR_ERR(local);
 		goto error_unlock;
@@ -434,7 +431,7 @@ static int rxrpc_sendmsg(struct socket *sock, struct msghdr *m, size_t len)
 			ret = -EAFNOSUPPORT;
 			goto error_unlock;
 		}
-		local = rxrpc_lookup_local(&rx->srx);
+		local = rxrpc_lookup_local(sock_net(sock->sk), &rx->srx);
 		if (IS_ERR(local)) {
 			ret = PTR_ERR(local);
 			goto error_unlock;
@@ -582,9 +579,6 @@ static int rxrpc_create(struct net *net, struct socket *sock, int protocol,
 
 	_enter("%p,%d", sock, protocol);
 
-	if (!net_eq(net, &init_net))
-		return -EAFNOSUPPORT;
-
 	/* we support transport protocol UDP/UDP6 only */
 	if (protocol != PF_INET &&
 	    IS_ENABLED(CONFIG_AF_RXRPC_IPV6) && protocol != PF_INET6)
@@ -780,8 +774,6 @@ static int __init af_rxrpc_init(void)
 
 	BUILD_BUG_ON(sizeof(struct rxrpc_skb_priv) > FIELD_SIZEOF(struct sk_buff, cb));
 
-	get_random_bytes(&rxrpc_epoch, sizeof(rxrpc_epoch));
-	rxrpc_epoch |= RXRPC_RANDOM_EPOCH;
 	get_random_bytes(&tmp, sizeof(tmp));
 	tmp &= 0x3fffffff;
 	if (tmp == 0)
@@ -809,6 +801,10 @@ static int __init af_rxrpc_init(void)
 		goto error_security;
 	}
 
+	ret = register_pernet_subsys(&rxrpc_net_ops);
+	if (ret)
+		goto error_pernet;
+
 	ret = proto_register(&rxrpc_proto, 1);
 	if (ret < 0) {
 		pr_crit("Cannot register protocol\n");
@@ -839,11 +835,6 @@ static int __init af_rxrpc_init(void)
 		goto error_sysctls;
 	}
 
-#ifdef CONFIG_PROC_FS
-	proc_create("rxrpc_calls", 0, init_net.proc_net, &rxrpc_call_seq_fops);
-	proc_create("rxrpc_conns", 0, init_net.proc_net,
-		    &rxrpc_connection_seq_fops);
-#endif
 	return 0;
 
 error_sysctls:
@@ -855,6 +846,8 @@ static int __init af_rxrpc_init(void)
 error_sock:
 	proto_unregister(&rxrpc_proto);
 error_proto:
+	unregister_pernet_subsys(&rxrpc_net_ops);
+error_pernet:
 	rxrpc_exit_security();
 error_security:
 	destroy_workqueue(rxrpc_workqueue);
@@ -875,14 +868,16 @@ static void __exit af_rxrpc_exit(void)
 	unregister_key_type(&key_type_rxrpc);
 	sock_unregister(PF_RXRPC);
 	proto_unregister(&rxrpc_proto);
-	rxrpc_destroy_all_calls();
-	rxrpc_destroy_all_connections();
+	unregister_pernet_subsys(&rxrpc_net_ops);
 	ASSERTCMP(atomic_read(&rxrpc_n_tx_skbs), ==, 0);
 	ASSERTCMP(atomic_read(&rxrpc_n_rx_skbs), ==, 0);
-	rxrpc_destroy_all_locals();
 
-	remove_proc_entry("rxrpc_conns", init_net.proc_net);
-	remove_proc_entry("rxrpc_calls", init_net.proc_net);
+	/* Make sure the local and peer records pinned by any dying connections
+	 * are released.
+	 */
+	rcu_barrier();
+	rxrpc_destroy_client_conn_ids();
+
 	destroy_workqueue(rxrpc_workqueue);
 	rxrpc_exit_security();
 	kmem_cache_destroy(rxrpc_call_jar);

net/rxrpc/ar-internal.h

@@ -11,6 +11,8 @@
 
 #include <linux/atomic.h>
 #include <linux/seqlock.h>
+#include <net/net_namespace.h>
+#include <net/netns/generic.h>
 #include <net/sock.h>
 #include <net/af_rxrpc.h>
 #include <rxrpc/packet.h>
@@ -64,6 +66,37 @@ enum {
 	RXRPC_CLOSE,			/* socket is being closed */
 };
 
+/*
+ * Per-network namespace data.
+ */
+struct rxrpc_net {
+	struct proc_dir_entry	*proc_net;	/* Subdir in /proc/net */
+	u32			epoch;		/* Local epoch for detecting local-end reset */
+	struct list_head	calls;		/* List of calls active in this namespace */
+	rwlock_t		call_lock;	/* Lock for ->calls */
+
+	struct list_head	conn_proc_list;	/* List of conns in this namespace for proc */
+	struct list_head	service_conns;	/* Service conns in this namespace */
+	rwlock_t		conn_lock;	/* Lock for ->conn_proc_list, ->service_conns */
+	struct delayed_work	service_conn_reaper;
+
+	unsigned int		nr_client_conns;
+	unsigned int		nr_active_client_conns;
+	bool			kill_all_client_conns;
+	spinlock_t		client_conn_cache_lock; /* Lock for ->*_client_conns */
+	spinlock_t		client_conn_discard_lock; /* Prevent multiple discarders */
+	struct list_head	waiting_client_conns;
+	struct list_head	active_client_conns;
+	struct list_head	idle_client_conns;
+	struct delayed_work	client_conn_reaper;
+
+	struct list_head	local_endpoints;
+	struct mutex		local_mutex;	/* Lock for ->local_endpoints */
+
+	spinlock_t		peer_hash_lock;	/* Lock for ->peer_hash */
+	DECLARE_HASHTABLE	(peer_hash, 10);
+};
+
 /*
  * Service backlog preallocation.
  *
@@ -211,6 +244,7 @@ struct rxrpc_security {
 struct rxrpc_local {
 	struct rcu_head		rcu;
 	atomic_t		usage;
+	struct rxrpc_net	*rxnet;		/* The network ns in which this resides */
 	struct list_head	link;
 	struct socket		*socket;	/* my UDP socket */
 	struct work_struct	processor;
@@ -601,7 +635,6 @@ struct rxrpc_ack_summary {
  * af_rxrpc.c
  */
 extern atomic_t rxrpc_n_tx_skbs, rxrpc_n_rx_skbs;
-extern u32 rxrpc_epoch;
 extern atomic_t rxrpc_debug_id;
 extern struct workqueue_struct *rxrpc_workqueue;
 
@@ -634,8 +667,6 @@ extern const char *const rxrpc_call_states[];
 extern const char *const rxrpc_call_completions[];
 extern unsigned int rxrpc_max_call_lifetime;
 extern struct kmem_cache *rxrpc_call_jar;
-extern struct list_head rxrpc_calls;
-extern rwlock_t rxrpc_call_lock;
 
 struct rxrpc_call *rxrpc_find_call_by_user_ID(struct rxrpc_sock *, unsigned long);
 struct rxrpc_call *rxrpc_alloc_call(gfp_t);
@@ -653,7 +684,7 @@ void rxrpc_see_call(struct rxrpc_call *);
 void rxrpc_get_call(struct rxrpc_call *, enum rxrpc_call_trace);
 void rxrpc_put_call(struct rxrpc_call *, enum rxrpc_call_trace);
 void rxrpc_cleanup_call(struct rxrpc_call *);
-void __exit rxrpc_destroy_all_calls(void);
+void rxrpc_destroy_all_calls(struct rxrpc_net *);
 
 static inline bool rxrpc_is_service_call(const struct rxrpc_call *call)
 {
@@ -773,7 +804,8 @@ int rxrpc_connect_call(struct rxrpc_call *, struct rxrpc_conn_parameters *,
 void rxrpc_expose_client_call(struct rxrpc_call *);
 void rxrpc_disconnect_client_call(struct rxrpc_call *);
 void rxrpc_put_client_conn(struct rxrpc_connection *);
-void __exit rxrpc_destroy_all_client_connections(void);
+void rxrpc_discard_expired_client_conns(struct work_struct *);
+void rxrpc_destroy_all_client_connections(struct rxrpc_net *);
 
 /*
  * conn_event.c
@@ -784,9 +816,6 @@ void rxrpc_process_connection(struct work_struct *);
  * conn_object.c
  */
 extern unsigned int rxrpc_connection_expiry;
-extern struct list_head rxrpc_connections;
-extern struct list_head rxrpc_connection_proc_list;
-extern rwlock_t rxrpc_connection_lock;
 
 int rxrpc_extract_addr_from_skb(struct sockaddr_rxrpc *, struct sk_buff *);
 struct rxrpc_connection *rxrpc_alloc_connection(gfp_t);
@@ -800,7 +829,8 @@ void rxrpc_see_connection(struct rxrpc_connection *);
 void rxrpc_get_connection(struct rxrpc_connection *);
 struct rxrpc_connection *rxrpc_get_connection_maybe(struct rxrpc_connection *);
 void rxrpc_put_service_conn(struct rxrpc_connection *);
-void __exit rxrpc_destroy_all_connections(void);
+void rxrpc_service_connection_reaper(struct work_struct *);
+void rxrpc_destroy_all_connections(struct rxrpc_net *);
 
 static inline bool rxrpc_conn_is_client(const struct rxrpc_connection *conn)
 {
@@ -828,7 +858,7 @@ static inline void rxrpc_put_connection(struct rxrpc_connection *conn)
  */
 struct rxrpc_connection *rxrpc_find_service_conn_rcu(struct rxrpc_peer *,
 						     struct sk_buff *);
-struct rxrpc_connection *rxrpc_prealloc_service_connection(gfp_t);
+struct rxrpc_connection *rxrpc_prealloc_service_connection(struct rxrpc_net *, gfp_t);
 void rxrpc_new_incoming_connection(struct rxrpc_connection *, struct sk_buff *);
 void rxrpc_unpublish_service_conn(struct rxrpc_connection *);
 
@@ -861,9 +891,9 @@ extern void rxrpc_process_local_events(struct rxrpc_local *);
 /*
  * local_object.c
  */
-struct rxrpc_local *rxrpc_lookup_local(const struct sockaddr_rxrpc *);
+struct rxrpc_local *rxrpc_lookup_local(struct net *, const struct sockaddr_rxrpc *);
 void __rxrpc_put_local(struct rxrpc_local *);
-void __exit rxrpc_destroy_all_locals(void);
+void rxrpc_destroy_all_locals(struct rxrpc_net *);
 
 static inline void rxrpc_get_local(struct rxrpc_local *local)
 {
@@ -901,6 +931,17 @@ extern unsigned int rxrpc_resend_timeout;
 
 extern const s8 rxrpc_ack_priority[];
 
+/*
+ * net_ns.c
+ */
+extern unsigned int rxrpc_net_id;
+extern struct pernet_operations rxrpc_net_ops;
+
+static inline struct rxrpc_net *rxrpc_net(struct net *net)
+{
+	return net_generic(net, rxrpc_net_id);
+}
+
 /*
  * output.c
  */

net/rxrpc/call_accept.c

@@ -38,6 +38,7 @@ static int rxrpc_service_prealloc_one(struct rxrpc_sock *rx,
 {
 	const void *here = __builtin_return_address(0);
 	struct rxrpc_call *call;
+	struct rxrpc_net *rxnet = rxrpc_net(sock_net(&rx->sk));
 	int max, tmp;
 	unsigned int size = RXRPC_BACKLOG_MAX;
 	unsigned int head, tail, call_head, call_tail;
@@ -79,7 +80,7 @@ static int rxrpc_service_prealloc_one(struct rxrpc_sock *rx,
 	if (CIRC_CNT(head, tail, size) < max) {
 		struct rxrpc_connection *conn;
 
-		conn = rxrpc_prealloc_service_connection(gfp);
+		conn = rxrpc_prealloc_service_connection(rxnet, gfp);
 		if (!conn)
 			return -ENOMEM;
 		b->conn_backlog[head] = conn;
@@ -136,9 +137,9 @@ static int rxrpc_service_prealloc_one(struct rxrpc_sock *rx,
 
 	write_unlock(&rx->call_lock);
 
-	write_lock(&rxrpc_call_lock);
-	list_add_tail(&call->link, &rxrpc_calls);
-	write_unlock(&rxrpc_call_lock);
+	write_lock(&rxnet->call_lock);
+	list_add_tail(&call->link, &rxnet->calls);
+	write_unlock(&rxnet->call_lock);
 
 	b->call_backlog[call_head] = call;
 	smp_store_release(&b->call_backlog_head, (call_head + 1) & (size - 1));
@@ -185,6 +186,7 @@ int rxrpc_service_prealloc(struct rxrpc_sock *rx, gfp_t gfp)
 void rxrpc_discard_prealloc(struct rxrpc_sock *rx)
 {
 	struct rxrpc_backlog *b = rx->backlog;
+	struct rxrpc_net *rxnet = rxrpc_net(sock_net(&rx->sk));
 	unsigned int size = RXRPC_BACKLOG_MAX, head, tail;
 
 	if (!b)
@@ -209,10 +211,10 @@ void rxrpc_discard_prealloc(struct rxrpc_sock *rx)
 	tail = b->conn_backlog_tail;
 	while (CIRC_CNT(head, tail, size) > 0) {
 		struct rxrpc_connection *conn = b->conn_backlog[tail];
-		write_lock(&rxrpc_connection_lock);
+		write_lock(&rxnet->conn_lock);
 		list_del(&conn->link);
 		list_del(&conn->proc_link);
-		write_unlock(&rxrpc_connection_lock);
+		write_unlock(&rxnet->conn_lock);
 		kfree(conn);
 		tail = (tail + 1) & (size - 1);
 	}